Effects of Growth Regulators and Explants on Callus Induction and Organogenesis in Hypericum perforatum

Hypericum perforatum is a traditional medicinal plant that has been used for the treatment of neurological disorders and depression. In this research, the effect of different levels of growth regulators (IAA and BAP) and explants type (root, stem, leaf) on callus induction and organogenesis of Hypericum perforatum were studied through factorial experiment design based on completely randomized arrangement with five replications and five samples per experimental unit. Explants from sterilized seedlings were cultured on MS medium containing different concentrations of IAA (0.0, 0.5, 1.0, and 2.0 mg L-1) and BAP (0.0, 0.4, and 0.8 mg L-1). We incubated the samples in the dark at 23 degrees C for 28 days. After this period, variables including callus size, number of roots and number of shoots were measured. Among tested explants, leaf explants was found to be most effective as it produced the most number of roots and shoots. The main effects of IAA and BAP and also the interaction or combination effects of these growth regulators were statistically significant (P <= 0.01) on all traits. The maximum number of shoots was obtained in leaf explants, when the concentration of BAP and IAA was high and low, respectively. Our findings are compatible with the results reported that in H. perforatum, BAP was found to be the most efficient in promoting shoot regeneration when leaves were used as the explants.